This invention relates to heat-transfer fluids.
Heat-transfer fluids are useful to transfer heat from a heat source to a heat sink. Heat-transfer fluids are useful, for example, in chemical manufacturing processes to heat and/or cool reaction mixtures.
It does not matter what the actual temperature of the heat source and heat sink are as long as the heat-transfer fluid is pumpable, can be contained in the process equipment and does not decompose at an unacceptable rate at the operational temperatures.
One useful heat-transfer fluid is the eutectic mixture of diphenyl oxide and biphenyl described in U.S. Pat. No. 1,882,809. A major drawback is the high freezing point of the mixture (54.degree. F.). Additives to this eutectic mixture such as biphenylphenyl ethers described in U.S. Pat. No. 3,888,777 lower the freezing point. However, some fluids have viscosities large enough to render the heat-transfer fluid unpumpable and thereby useless as heat-transfer fluids at temperatures far above their freezing points.
It would be desirable to have a heat-transfer fluid which is useful at low temperatures as well as high temperatures.